[RPG] How would combat work without opportunity attacks


Opportunity attacks have a long history in the world of tabletop games and D&D in particular. 3.5e/PF both had an exhaustive list of actions which can or can not trigger an OA.

Various games have their own OA mechanics, but one trigger always remains the same.

  • 5th edition simplified things a lot. Only the one single trigger left:

    You can make an opportunity attack when a hostile creature that you can see moves out of your reach.

  • Starfinder also reduces the list of AoO triggers greatly, comparing to its ancestor, to three points only, and "an enemy goes away" trigger is still there:

    When you threaten a space and the opponent moves out of that space in any way other than a guarded step

  • Open Legend, a game influenced by but not directly derived from D&D, has the same only one trigger:

    If you are wielding a melee weapon, and an enemy moves from a space within your reach to a space that is not within your reach, you may make a free attack against the enemy.

It seems the game developers consider this particular trigger as the most important one. To my knowledge, many wargames uses the similar rule. So what happens if we remove it? Why do we need it, in the first place?

Is there a substantial problem with turn-based gameplay, which OAs solve?

The reason I ask is because there are 5e-based games which do not have OAs at all (Five Torches Deep, for instance). I want to know what changes I should expect within basic 5e gameplay (no feats, no variant rules) if the DM introduces a "no opportunity attacks" house rule.

I'm more interested in base mechanics, rather than particular OA-dependent 5e spells or features (like Rogue's Cunning Action becomes less useful, etc.)

Best Answer

Coming from a D&D point of view...

The game becomes a lot more mobile, speed is more valuable, the concept of front-liner diminishes, and being at range is either difficult or not important.

I tried this for a one-shot once with a couple of new players, and we removed OAs for simplicity's sake. The more experienced players at the table had some fun exploring the consequences of this.


Everyone runs in, attacks, runs away. Both enemies and party members take advantage of cover and we noticed that the disposition of units in the map was much more chaotic.

Speed is more valuable

If mobility is heightened, then speed will improve accordingly. Both the Tabaxi and the Monk appreciated jumping into backlines without hassle and focusing on the squishy ranged goblins that were harassing them.

Frontliners can't frontline as well

One of the reasons a Barbarian or a Fighter stands in front of the party and prevents multiple enemies from going near the Wizards and Sorcerers in the back is their menacing presence and the threat of retaliation. Without AoO, enemies could easily run around and jump into backlines, and the party's melee frontliners just did the same.

Being at a range is more difficult, but at the same time, possibly unnecessary

In closed off areas, where you can't be shooting your bow from 150 ft away, enemies quickly get the jump on ranged attackers, and new tactics are required. If the character is at a range because it does more damage (Dex Fighter with Sharpshooter feat), then they can just step 5 ft from any enemy and attack. If they are at a range because they are very squishy (Wizard with 0 CON modifier), they require new tactics to always be at a distance.

Cat and Mouse

While it didn't happen to us, in open areas, a game of cat and mouse can arise. Goblin dashes to Wizard. Wizard Dashes away. Gobling Dashes to Wizard. Repeat. Because there is no consequence for running away, kiting enemies is easier (you don't take damage for running) in wide spaces.

Overall, it was a fun experience for players, but we decided it didn't work for us. The players enjoyed the fact that, originally, their front-liners were there preventing enemies from running through them. They didn't enjoy enemies now running away and kiting them. But to each their own.

Is there a substantial problem with turn-based gameplay, which OAs solve?

I would say it depends on your expectation. I've only ever played D&D 5e, and I expect our melee combatants to have some ways of preventing enemies from running past them. OAs are one way (a big one, as every character has access to them, from Barbarians to pets). If you don't have such an expectation, I don't see it becoming a big issue. You will simply build your ranged characters expecting to have to handle melee enemies often. All that being said, this is a mere opinion, and to each his own.